The present invention relates to a new and improved method of intermittently dressing an axially adjustable plate-shaped or dished grinding wheel of a gear grinding machine.
Generally speaking, the invention is concerned with a gear wheel-dressing method wherein the position of the ring-shaped portion or active rim of the grinding wheel is controlled and the grinding wheel is advanced or adjusted such that the active rim is retained at the same location independent of its wear. The active rim is dressed one respective time within a predetermined dressing interval by means of at least one likewise axially advancable dressing tool.
In order to obtain a high cutting efficiency of heavy-duty grinding wheels during grinding of gears, there prevails an important requirement as concerns dressing of the grinding wheel to prevent grinding wheel burn. Under the term "dressing" as used herein there is to be understood an operation by means of which there is reestablished at the grinding wheel its original contour and sharpness. Therefore, this operation also is referred to as resharpening of the grinding wheel. Diamonds are predominantly used as the dressing tools.
Now there are known to the art, for instance from German Patent Publication No. 25 53 510, equipment wherein a grinding wheel, for the dressing thereof, is brought from a work position into a dressing position and after the dressing operation is again returned back from the dressing position into a work position. This positional shifting of the grinding wheel is accomplished by means of a feed drive or gearing which compensates for the wear of the dressing tool during movement of the grinding wheel from the dressing position to the work position. Such type apparatuses are quite complicated in their construction and require an appreciable amount of time for the dressing of the grinding wheel.
Further, there are known to the art from the Publication "Taschenbuch der Maag-Zahnrader AG" (Maag Gear Book, Calculation and Manufacture of Gears and Gear Drives for Designers and Works Engineers, Zurich 1963 Edition, equipment resorting to manual axial adjustment or feed of the dressing tool in or towards the direction of the ring-shaped surface or active rim of the grinding wheel which is to be resharpened. Superfluous compensating advance or feed movements of the dressing tool can produce useless dressing losses of the grinding wheel and losses in accuracy during the grinding process, whereas required but unaccomplished compensating advance or feed movements can result in grinding wheel burn. The absolute dependency of the manual operation upon the experience and dexterity of the operator constitutes one of the basic drawbacks of this system.